1. Field of the Invention
The present invention relates to a drawing mechanism associated with a dobby or with another weave system for the formation of the shed on a weaving loom. The invention also relates to a process for manufacturing such a mechanism and to a weaving loom incorporating such a mechanism.
2. Brief Description of the Related Art
In the domain of dobbies, drawing mechanisms are known, comprising connecting rods which ensure the coupling of the mobile actuation members with the vertically mobile heddle frames mounted on the loom. In the conventional devices, the connectors of connecting rods are not dismountable. Plates are made at the ends of the connecting rods by cut-out, which has the effect of mechanically weakening these connecting rods. FR-A-2 676 467 discloses a drawing mechanism which partly solves these problems, in which a tubular connecting rod of flattened cross-section is provided with a connector comprising two plates provided to be disposed on either side of an oscillating lever. The two devices described in this document include relatively complex pieces provided to be inserted in the end of a connecting rod, these pieces being in practice difficult to manufacture on an industrial scale at an acceptable cost. Furthermore, FR-A-2 776 307 describes another drawing mechanism in which two substantially parallel pins are immobilized within a connecting rod by adherence, these two pins being maintained spaced apart from each other by means of screws.
The increase of the operational speeds of the drawing mechanisms is such that the elements constituting these mechanisms are subject to considerable accelerations, particularly during reversals of movement, which involves exerting intense efforts of blocking by the use of increasingly numerous screws. This is detrimental to the rapidity of manoeuvre of these devices and to their cost price, while the maintenance interventions on these devices are more and more complex.
It is a more particular object of the present invention to overcome these drawbacks by proposing a drawing mechanism in which a firm relative immobilization of the parts constituting this device is obtained without resorting to too large a number of screws.